Index: error_code.cpp
===================================================================
--- error_code.cpp	(revision 48001)
+++ error_code.cpp	(working copy)
@@ -79,7 +79,8 @@
   # if defined(BOOST_WINDOWS_API) || defined(__hpux) || defined(__sun)\
      || (defined(__linux) && (!defined(__USE_XOPEN2K) || defined(BOOST_SYSTEM_USE_STRERROR)))\
      || (defined(__osf__) && !defined(_REENTRANT))\
-     || (defined(__vms))
+     || (defined(__vms))\
+     || (defined(__QNXNTO__))
       const char * c_str = std::strerror( ev );
       return std::string( c_str ? c_str : "Unknown error" );
   # else
@@ -157,7 +158,9 @@
     case EALREADY: return make_error_condition( connection_already_in_progress );
     case EBADF: return make_error_condition( bad_file_descriptor );
     case EBADMSG: return make_error_condition( bad_message );
+  # if EALREADY != EBUSY // QNX treats EALREADY and EBUSY as the same value
     case EBUSY: return make_error_condition( device_or_resource_busy );
+  # endif // EALREADY != EBUSY
     case ECANCELED: return make_error_condition( operation_canceled );
     case ECHILD: return make_error_condition( no_child_process );
     case ECONNABORTED: return make_error_condition( connection_aborted );